interrupt switch and cabel adjustment alpha 1

[man-of-war]

i have an 86-89 alpha 1 im trying to adjust the cable's .i went to mercstuff.com and did the lower shift cable adjustment.but their is another cable next to the shift cable, this cable has a barell adjustment and a stud bolt goes through it how do i adjust this cable. and what is that cable used for.

 

[Laddies]

Re: interrupt switch and cabel adjustment alpha 1

Thats the outer shift cable leave it alone, once installed and adjusted to leagth it is not adjustable--Bob

 

[man-of-war]

Re: interrupt switch and cabel adjustment alpha 1

what function does this cable preform? the interrupt switch,I know it works by pushing the wheel in while the engine is runing it stalls.but while the engine is idleing and i shift into a gear it sounds like alot of grinding in the outdrive.what should i look for to know if the interrupt switch is being moved or is their an adjusting . i had my xyl shift to foward then to reverse [with engine off] and i did not see the interrupt switch wheel move at all.THANKS FOR THE HELP

 

[Don S]

Re: interrupt switch and cabel adjustment alpha 1

With an Alpha drive, the interrupt switch is NOT used when putting the drive in gear. To keep the ratchiting to a minimum, put the drive in gear quickly, one or maybe 2 clicks before you have it all the way into gear. Going slow is destroying the shift dogs of your drive.<br />Because of the reverse cut on the shift dogs, the drive stays in gear when you put it there. Without that reverse cut the drive would constantly slip out of gear. The shift interrup switch does nothing more than makes the engine hicup for a split second to allow the pressure to come off the reverse cut gears so it will come out of gear.<br />Adjust the system like the manual says, not how you think it should work.<br />Here is a link to an online Mercruiser manual for your drive with complete details on adjustment.<br /><br /> http://www.boatfix.com/merc/Servmanl/6/6covr3.pdf

 

[Ralph 123]

Re: interrupt switch and cabel adjustment alpha 1

Don, does that procedure work for all the shift plates? In particular, will it work on the engine mounted plate? I have 3 different procedures (the one from that manual, the one from my Seloc manual and the one from Mercstuff) and they are all different...

 

[man-of-war]

Re: interrupt switch and cabel adjustment alpha 1

Don S thanks for the manual very informative.does it matter if the power [purple wire] from the ignition key goes to the interrupt switch ? or should it come fron the distributor[green/white] ? when i got the boat the wires were coming from the key ignition ,the michanic has it coming from the distributor green and white . thanks

 

[Don S]

Re: interrupt switch and cabel adjustment alpha 1

Ralph:<br />The manual link I gave is from Mercruiser and is THE manual that the marine techs use. They do not use Mercstuff, Seloc, or Clymers........<br /><br />MOW<br />What engine (model and year) do you have? The drive manual gives cable adjustment, not wiring diagrams. For that you need an engine manual.

 

[Ralph 123]

Re: interrupt switch and cabel adjustment alpha 1

I'm not sure that one (SM 6) covers my S/N range and that may be the issue. That seems to cover the vertical mounted plate not the horizontal plate that's in my 1979s. Seloc has 2 procedures one that 1973-1982 then a different one called "since 1983"

 

[man-of-war]

Re: interrupt switch and cabel adjustment alpha 1

engine specifications gm, model 75, 454/7.4, with a thunderbolt IV

 

[Don S]

Re: interrupt switch and cabel adjustment alpha 1

Ralph, this thread is about 86 to 89 Alpha's, I assumed your's was the same. Best to start a seperate thread with your's, it's different.<br /><br />MOW Can I assume that "model 75" was supposed to mean it's a 1985 model? Merc didn't use any 454's in 75, I'm not sure they were even out then. But could be wrong about that.

 

[Don S]

Re: interrupt switch and cabel adjustment alpha 1

MOW<br />Here is a basic Thunderbolt IV, V8 wiring diagram.<br /><br />

 

[man-of-war]

Re: interrupt switch and cabel adjustment alpha 1

i used the casting # from the engine and got a printout from AERA engine rebuilders association.and it reads [manufacturer.....GM] [MODEL/YEAR....75] [L/CID/VIN...7.4/454/L] [#OF CYLINDERS...8] [COMPRESSION RATIO...7.9;1 RATIO]

 

[Ralph 123]

Re: interrupt switch and cabel adjustment alpha 1

Thanks for the help Don.